Find the value of y (view picture below)

One expression below in undefined, and the other expression has a well defined value. which expression is undefined and explain why it has no value. which expression is defined? what is the value of that expression and how do you know? what is a different expression using a trig inverse function that is also undefined?

The function models the number of accidents per 50 million miles driven as a function

The complement of an angle is one-sixth the measure of the supplement of the angle. what is the measure of the complement angle?